if you are using koh then yes, but I'd demeth, and compost it first. We use naoh and demeth. anything spilled makes great weed killer due to the soaps and sodium. I don't know where the article came from, but there was an article link some where on infopop that showed a picture of a huge fish kill on a river that was next to a field that a biodiesel producer was using to land apply glycerin that had not been demethed. I sure someone else with more working brain cells will chime in and help me out here. I'd love to try spraying a road for dust, but I'm worried about run off.

powering 2 bobcats, an excavator, and a ventrac mower. looking for a diesel weedeater!

You have to keep doses small. There was a biodiesel producer a few years back that was spraying thousands of gallons of raw glycerin onto fields. They overloaded the fields with the stuff and it seeped into a nearby stream. They were caught and fined.

So, if you are going to spray it, you should test somehow to make sure it's breaking down and not seeping away.

Glycerin by itself is not a fertilizer, but it breaks down into one. I live in a dry, alkaline environment, and I've used glycerin to kill the weeds on my fencelines and gravel roads for nearly a decade. Be warned, once you start using it as a weed killer you're pretty well committed to continuing to use it. After a year the raw glycerin will have broken down into fertilizer, encouraging things to grow where you applied it. Seeds and roots readily soak up the glycerin, which kills and preserves them for a while, until they, too, turn into fertilizer. I've read of reacting glycerin with Sulfuric acid to rapidly create fertilizer, but have not tried it myself. I also compost some of my left-over glycerin. A nearby biodiesel plant send their raw glycerin to a dairy with a large methane digester, powering a pair of large gensets. The output from the digester is also good fertilizer, with the benefit of capturing some of the energy along the way.Hopefully this is enough to give you some ideas of the best use in your situation.Cheers,JohnO